Variation of sprinkler irrigation in relation to water infiltration and distribution in soils of western of Romania

This study reports the development and testing of a model which relates yield to irrigation amount and uniformity. Required input data are the Christiansen uniformity coefficient (CUC) and a parameter describing the sensitivity of crop yield to water deficits obtained from empirical relationships between evapotranspiration and crop yield. The model was used to determine optimum irrigation amounts for forestry nursery under sprinkler irrigation in soils of western Romanian. The research was carried out in the Iarac forestry nursery in the Iuliu Moldovan Forest District during 2012-2014, on an alluvial soil (the vertical-gleyed subtype). The placement of the sample markets was carried out according to the "divided parcels method" in two repetitions, and the surface of a parcel was 450 m 2 . At the time when the measurements were taken, the meteorological conditions were: temperature of 23 o C; wind speed of 1.5 m s -1 ; total nebulosity 3; and relative humidity 47. The paper work displays the results obtained after the sprinkler irrigation, when we determined the quantity of water spread by the 6 sprinklers on a 15 m-radius, placed on the direction of the cardinal points and values of water infiltration after 24 hours by sprinkler irrigation. The purpose of this research is to emphasize the variation of the water infiltration after sprinkler irrigation correlated with the uniformity coefficient (Cristiansen) and the soil granulometry of the experimental field. This correlation is important, because the soil moisture values measured at a certain time frame after irrigation consists in an important parameter for the optimal amount of water supplied per unit area assessments. The results show that the optimum irrigation amount depends on irrigation uniformity, and on agronomic and physical properties of soil.